1. Field of the Description
The present description relates, in general, to amusement park rides and passenger restraints with latching and locking mechanisms (such as ratchet and pawl assemblies) in such rides and other implementations, and, more particularly, to a ratchet and pawl assembly for use in latching and/or locking a passenger restraint, with the assembly adapted to provide improved, positive engagement between the pawl and the ratchet.
2. Relevant Background
Amusement parks continue to be popular worldwide with hundreds of millions of people visiting the parks each year. Park operators seek new designs for extreme or thrill rides that attract people to their parks, but safe operation of the new and existing rides is always a highest priority design requirement. For example, roller coasters and other thrill rides apply significant amounts of force (e.g., g-forces) on the passenger with numerous twists, turns, drops, and loops at speeds of up to 100 miles per hour or more. Ride designers or engineers are given the task of producing unique and more exciting rides that are safe and that are also less costly to operate and maintain.
Passenger restraints are one of the most important features in ride safety as these restraints comfortably and securely keep passengers in place in a seat or within a ride car or compartment. Ride engineers continue to evaluate new kinds of passenger restraint systems that meet safety requirements while being less expensive to operate and maintain. During operation of a ride, a passenger restraint is typically placed across the lap or over the shoulder of a ride passenger, and a mechanism is typically provided as part of the restraint that locks or latches the restraint in place during operation of the ride. Proper operation for passenger restraints includes the locking or latching mechanism properly engaging (sometimes labeled “positive engagement”) to prevent the restraint from opening during the ride cycle.
Ratchets are convenient devices for ride designers to use in passenger restraint assemblies because they rotate in one direction but not in the other when a pawl engages teeth of the ratchet or the ratchet wheel. For example, an over-the-shoulder restraint may include a pawl and ratchet assembly to provide the latching and locking mechanism for the restraint. During operation, the passenger pulls the restraint down, and, during this motion, a spring or other actuator urges the pawl into engagement with the teeth of the nearby or adjacent ratchet. As a result, the passenger moves the restraint and the ratchet in one direction (e.g., downward), but the passenger and ride forces cannot push or move the restraint and the ratchet in the other direction because the pawl engages the ratchet teeth to stop motion in this direction. Pawl and ratchet assemblies are also relatively inexpensive to manufacture and maintain, and these and other characteristics make ratchets attractive for use in restraints and similar applications.
To be confident that the restraint will adequately prevent reverse motion when needed, a ride designer needs to design the pawl and ratchet assembly to ensure positive engagement. The design should be adapted to allow the pawl to move freely, as it passes over the teeth in the forward motion of the ratchet, and then into the valley or recessed surface between two adjacent teeth of a ratchet to engage the ratchet and to resist reverse motion if movement of the ratchet is attempted in this second or reverse motion.
Passenger restraints of all kind may be designed to include pawl and ratchet assemblies and exemplary passenger restraints include over-the-shoulder restraints, shoulder or lap belts, bar, or other restraints for amusement park rides, automobiles, airplanes, trains, ski-chair lifts, and the like. Additionally, there are other applications where it is desirable to monitor proper operation of a locking or latching mechanism such as a pawl and ratchet assembly. For example, the shipping industry utilizes tie downs to secure cargo during transport by ship, train, truck, airplane, or the like, and the tie downs are secured to avoid excessive movement of the cargo when forces are applied. In these cases, pawl and ratchet assemblies may be utilized, and an operator needs to be able to trust or to verify proper engagement and operability of any biasing components. As another example, in factory environments, pawl and ratchet assemblies may be used to limit conveyor belt or other moving part motion to a single direction, e.g., a conveyor belt cannot roll backwards.
There remains an ongoing need for pawl and ratchet assemblies that operate effectively to achieve full or positive engagement between the pawl and the ratchet. Preferably, such pawl and ratchet assemblies would be relatively simple in design, would operate automatically and/or without requiring visual verification of engagement, and would be useful with restraint systems such as passenger restraints used in vehicles of amusement park rides and other vehicles.